Study on frost heave force characteristics of fractured rock mass based on borehole expansion theory

In order to study the freezing of fractured rock strata affected to the safety and stability of freezing wall and freezing shaft liner during the ground freezin g construction method applied to mine shaft construction in West China, based on the borehole expansion theory of geomaterials, a plane strain mechanics model of fro st heave force was established under the freezing role of fractured rock mass and a comparison analysis was conducted between theoretical analysis results and study results and photo-elastic model tests. The results showed that the theoretical calculation of frost heave force would mainly be depended on physical mechanics charact eristics of fractured rock mass and water-ice medium and the heave coupling relationship between the fractured volume and the water-ice medium. During the freezing process, when the equivalent heave coefficient of the water-ice medium would be different, the frost heave force occurred at fractured wall and radial stress in the fract ured rock mass would be different. With the comparison analysis, the validity of solution was verified. In the test of photo-elastic model, the stress in the fractured rock mass location closed to fractures would be higher.